Data storage in the computer industry is accomplished in a number of ways. For example, data may be stored on tape, compact disk, "floppy" or "hard" disk, and the like. Oftentimes, data storage media which is transferrable from one location to another is housed within a parallelepiped-shaped cartridge. Data storage systems are used to store data storage media devices such as data cartridges at known locations and to retrieve desired cartridges so that data may be written to or read from the cartridges. Such data storage and handling systems are often referred to as "juke box" data storage systems, particularly if they can accommodate a large number of individual data cartridges.
A data storage handling system may include a cartridge engaging assembly or "picker" which is adapted to retrieve a data cartridge and transfer the cartridge from one location to another, such as from a cartridge storage array to a read/write drive. The drive may then be used to read data from or write data to the cartridge. Once the read/write operation is complete, the cartridge engaging assembly may withdraw the data cartridge from the drive and return it to the appropriate location within the cartridge storage array.
A cartridge engaging assembly may be comprised of one or more latching "fingers" that are adapted to hook into notches in a data cartridge. The fingers may be pivotally attached to a motor-driven, laterally extending "thumb" member which is adapted to translate the fingers in a longitudinal direction as well as push a cartridge out of the cartridge engaging assembly. The latching and releasing of a cartridge by a finger is typically accomplished by the longitudinal translation of the thumb in cooperation with some type of finger guide assembly.
One type of finger guide assembly provides the fingers with guide posts which run along elongate tracks within the cartridge engaging assembly. Each of the elongate tracks typically has at least two branches, an inner branch and an outer branch, which provide different paths on which the fingers may travel. The fingers may be attached to a biasing member such as a spring which urges them inwardly and forces the fingers to follow an inward most path when they are not grasping a cartridge. An outermost path may also be provided which forces the fingers to splay outwardly to release a cartridge. In cartridge handling assemblies with relatively long fingers, the width of each elongate track, including the innermost path and the outermost path, must also be relatively wide. The longer the fingers, the farther they splay outwardly as the thumb travels forwardly. The width of the elongate tracks is directly related to the overall width of the cartridge handling assembly.
One or more one-way gates may be positioned on the elongate tracks which guide the fingers to particular paths depending on the desired operation. A one-way gate allows a finger guide post to pass when the thumb and finger are traveling in a certain longitudinal direction, either forwardly or rearwardly. When the thumb and finger are traveling in the opposite direction, the one-way gate blocks the path and forces the finger onto a different path. A gate typically comprises some type of biasing member which allows it to move out of the path of a finger guide post.
Cartridge engaging assemblies such having features discussed above are described in U.S. Pat. No. 5,014,255 for OPTICAL DISK CARTRIDGE HANDLING APPARATUS WITH PASSIVE CARTRIDGE ENGAGEMENT ASSEMBLY; U.S. Pat. No. 5,010,536 for CARTRIDGE HANDLING SYSTEM; and U.S. Pat. No. 5,043,962 FOR CARTRIDGE HANDLING SYSTEM, which are each hereby specifically incorporated for all that is contained therein. Each of the above references illustrate a two-finger assembly, each of the fingers being attached to a thumb, and a forwardly-positioned gate. A cartridge engaging assembly with a relatively long, one-finger assembly attached to a thumb and a rearwardly-positioned gate is described in U.S. patent application Ser. No. 08/641,442 filed Apr. 29, 1996 for SINGLE-SIDE ENGAGING PICKER FOR DATA CARTRIDGES, which is hereby specifically incorporated for all that is contained therein. Such a one-finger assembly may be used for handling DLT tape cartridges with only one notch therein.
Thus, there exists a need for a finger assembly which is simply constructed and minimizes the use of attachments and biasing members. It would be most desirable to provide a floating finger assembly which is completely detached from the thumb, whereby the length of the fingers does not affect the necessary width of the elongate tracks, and thus the overall width of the cartridge handling assembly. A floating finger assembly accomplishes this by allowing the thumb to move forwardly independently of the fingers. The lateral space required by the slight lateral movement of floating fingers is usually considerably less than the lateral space required for relatively long fingers to rotate and splay outwardly with the forward movement of the thumb. Preferably, such a floating finger assembly should be quickly and easily recoverable should a floating finger be displaced.
There also exists a need for a flexible gate assembly which is also simply constructed and minimizes the use of attachments and biasing members. The flexible gate assembly would preferably be positioned at the forward end of the elongate track, rather than the rear end, so that the length of the elongate track is minimized.